Medical device tube having a suction lumen and an associated suctioning system

ABSTRACT

Various embodiments of a tracheal tube having a suction lumen are provided. For example, the suction lumen may be associated with two spaced apart pressure transducers, whereby a pressure drop between the transducers indicates that the suction lumen is free of blockages and a characteristic lack of pressure drop and/or particular pressure curve is indicative of a blockage. In addition, embodiments may include a tracheal tube with sensors configured to sense a buildup of secretions. The sensors may be located proximate to an opening in the suction lumen. In other embodiments, a blockage-clearing system for a suction lumen may be provided that blows air into the suction lumen to clear blockages. In particular, in certain embodiments, the blockage-clearing system may operate to create its own pressurized air source by utilizing the pressure change created in the suction line by a blockage.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/847,795 filed Jul. 30, 2010, the contents of which are herebyincorporated by reference in their entirety.

BACKGROUND

The present disclosure relates to tracheal tubes used in medicalapplications and, more particularly, to tracheal tubes having suctionslumens for suctioning secretions above a sealing cuff and systems forcontrolling the suctioning.

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present disclosure,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentdisclosure. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

In the course of treating a patient, a tube or other medical device maybe used to control the flow of air, food, fluids, or other substancesinto and out of the patient. For example, medical devices, such astracheal tubes, may be used to control the flow of air or other gasesthrough a trachea of a patient. Such tracheal tubes may includeendotracheal tubes (ETTs), tracheostomy tubes, or transtracheal tubes.In many instances, it is desirable to provide a seal between the outsideof the tube or device and the interior of the passage in which the tubeor device is inserted, such as the trachea. In this way, substances canonly flow through the passage via the tube or other medical deviceinserted in the tube, allowing a medical practitioner to maintaincontrol over the type and amount of substances flowing into and out ofthe patient. In addition, a high-quality seal against the trachealpassageway allows a ventilator to perform efficiently.

Such tracheal tubes are often coupled to an air source, such as aventilator, to provide the patient with a source of fresh air that istransferred through a main ventilation lumen adapted to allow airflow toand from the patient during inspiration and expiration, respectively.However, it may be desirable for additional functionalities to beprovided by the tracheal tube. For example, a tracheal tube may includea suction lumen that runs the length of the tube and that terminates atan aperture located above the inflatable cuff The suction lumen may beused for suctioning patient secretions from the mouth and upper airwaythat flow down into the trachea and accumulate above the inflatable cuffor on the tube. Although the evacuation process may provide for removalof secretions, it may be possible for the aperture to be come occluded,in particular because patient secretions may be relatively viscous andthe aperture is small.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the disclosed techniques may become apparent upon readingthe following detailed description and upon reference to the drawings inwhich:

FIG. 1 is a perspective view of an exemplary tracheal ventilation systemwith a suction lumen coupled to two pressure transducers;

FIG. 2A is a graph of the pressure over time for a first pressuretransducer of FIG. 1 during intermittent suctioning;

FIG. 2B is a graph of the pressure over time for a second pressuretransducers of FIG. 1 during intermittent suctioning;

FIG. 2C is a graph of the pressure over time for a differential betweenthe two pressure transducers of FIG. 1 during intermittent suctioning;

FIG. 3 is a flow diagram of a method of controlling suctioning that maybe used in conjunction with the system of FIG. 1;

FIG. 4 is an elevation view of an exemplary tracheal tube with asecretion sensor;

FIG. 5 is a side view of an exemplary tracheal tube with a secretionsensor inserted into a patient trachea;

FIG. 6 is a side view of an alternative arrangement of a tracheal tubewith a circumferential secretion sensor;

FIG. 7 is a side view of an alternative arrangement of a tracheal tubewith a secretion sensor associated with an alternate suction lumen;

FIG. 8 is a diagramatic view of an exemplary tracheal suctioning system;and

FIG. 9A is a cross-sectional view of an exemplary tracheal suctioningsystem that used the suction line to pressurize air; and

FIG. 9B is a cross-sectional view of the tracheal suctioning system ofFIG. 9A in which the air is released into the suction line.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

One or more specific embodiments of the present techniques will bedescribed below. In an effort to provide a concise description of theseembodiments, not all features of an actual implementation are describedin the specification. It should be appreciated that in the developmentof any such actual implementation, as in any engineering or designproject, numerous implementation-specific decisions must be made toachieve the developers' specific goals, such as compliance withsystem-related and business-related constraints, which may vary from oneimplementation to another. Moreover, it should be appreciated that sucha development effort might be complex and time consuming, but wouldnevertheless be a routine undertaking of design, fabrication, andmanufacture for those of ordinary skill having the benefit of thisdisclosure.

After a tracheal tube has been inserted into a patient airway, anassociated balloon cuff is inflated to form a seal within the trachealspace. The inflated cuff forms a shelf that blocks secretions from themouth from traveling into the lungs. Over time, the secretions may buildup on the top of the cuff and leak down into the lower airway if theseal against the tracheal walls becomes degraded. Accordingly, trachealtubes may include dedicated lumens with apertures located above thecuff. When a suction force is applied to the suction lumen, secretionsare taken up into the lumen through the aperture. This suctioningprocess may be performed on a regular basis, because tracheal tubes aretypically used for days or weeks before being replaced. When theaperture becomes occluded, e.g., because the secretions are viscous, itis impractical to replace the tracheal tube with a fresh tube with aclear suctioning lumen. Accordingly, it is desirable to be able todetect and clear any blockages in the suction lumen so that suctioningmay continue.

Provided herein are tracheal tubes that include lumens for suctioningsecretions that may accumulate on an inflated cuff. For example, thelumens may be associated with suction systems that are capable ofalternating positive and negative pressure to clear blockages in thesuction lumen. The tracheal tubes may also include one or more sensorsfor determining if the suction lumens are blocked. Additionally, thetracheal tubes may include sensors for determining the presence ofand/or the extent of secretion build-up. Also provided herein aresystems for communicating with the tracheal tubes and associated sensorsto inform clinicians if a suction lumen is blocked or if secretions havebuilt up on the cuff.

In certain embodiments, the disclosed tracheal tubes, systems, andmethods may be used in conjunction with any appropriate medical device,including a feeding tube, an endotracheal tube, a tracheotomy tube, acircuit, an airway accessory, a connector, an adapter, a filter, ahumidifier, a nebulizer, nasal cannula, or a supraglottal mask/tube. Thepresent techniques may also be used to monitor any patient benefitingfrom mechanical ventilation, e.g., positive pressure ventilation.Further, the devices and techniques provided herein may be used tomonitor a human patient, such as a trauma victim, an intubated patient,a patient with a tracheotomy, an anesthetized patient, a cardiac arrestvictim, a patient suffering from airway obstruction, or a patientsuffering from respiratory failure.

FIG. 1 shows an exemplary tracheal tube system 10 that has been insertedinto the trachea of a patient. The system 10 includes a tracheal tube12, shown here as an endotracheal tube, with an inflatable balloon cuff14 that may be inflated to form a seal against the tracheal walls. Asuction lumen 16 terminating in opening 18 may be disposed on thetracheal tube 12. As shown, an exterior suction tube 20 connects to thesuction lumen 16 for the removal of suctioned fluids. The suction tube20 may connected to a vacuum source 22 and fluid collection canister 23via additional connecting tubes. The suction tube 20 and suction lumen16 are in fluid communication with a pressure transducer 24 and apressure transducer 26. As provided herein, information about pressureat the pressure transducer 24 and the pressure transducer 26 may be usedto determine information about the suction lumen 16.

The pressure transducer 24 and the pressure transducer 26 are spacedapart so that a pressure drop between them may provide information aboutpotential blockages in the suction lumen 16. Generally, the pressuretransducer 26 located closer to a patient end will experience higherpressure than the pressure transducer 24 located closer to the vacuumsource 22 during suctioning of a clear, unblocked lumen. Accordingly,any change from this expected pressure drop between the pressuretransducer 24 and the pressure transducer 26 may be indicative of ablockage in the suction lumen 16.

As noted, the pressure transducer 24 and the pressure transducer 26 maybe associated with the suction lumen 16 and the suction tube 20. To thatend, they may be directly mounted onto one or both of the suction lumen16, the suction tube 20, or any associated tubes, side arms, orconnectors in the flow path from the suction lumen 16 to the vacuumsource 22, including the fluid collection canister 23. As shown, thepressure transducer 24 is coupled to the fluid collection canister 23.In other configurations, the pressure transducers 24 and 26 may bedisposed within a shunted pathway from suction tube 20 and fluidcollection canister 23. Further, in certain embodiments, a differentialpressure sensor may be employed. In certain embodiments, a connectingtube that includes the pressure transducer 24 and the pressuretransducer 26 and that is adapted to connect to the suction tube 20 maybe packaged with the tracheal tube 12 to be sold as a kit. Further, incertain embodiments, the pressure transducer 24 and the pressuretransducer 26 may be coupled via electrical leads or other connectionsto a connector 28 that may facilitate connection of the pressuretransducers 24 and 26 to a medical device, e.g., a patient monitor 32.

The system 10 may also include a respiratory circuit (not shown)connected to the endotracheal tube 12 that allows one-way flow ofexpired gases away from the patient and one-way flow of inspired gasestowards the patient. The respiratory circuit, including the tube 12,suction lumen 16, and suction tube 20, may include standard medicaltubing made from suitable materials such as polyurethane, polyvinylchloride (PVC), polyethylene teraphthalate (PETP), low-densitypolyethylene (LDPE), polypropylene, silicone, neoprene,polytetrafluoroethylene (PTFE), or polyisoprene. The cuff 14 is formedfrom material having suitable mechanical properties (such as punctureresistance, pin hole resistance, tensile strength), chemical properties(such as biocompatibility). In one embodiment, the walls of the cuff 14are made of a polyurethane having suitable mechanical and chemicalproperties. An example of a suitable polyurethane is Dow Pellethane®2363-80A. In another embodiment, the walls of the cuff 14 are made of asuitable polyvinyl chloride (PVC). In certain embodiments, the cuff 14may be generally sized and shaped as a high volume, low pressure cuffthat may be designed to be inflated to pressures between about 15 cm H₂Oand 30 cm H₂O. Additionally, it should be noted that the cuff 14 may beany suitable cuff, such as a tapered cuff, a non-tapered cuff, and soforth.

The system 10 may also include devices that facilitate positive pressureventilation of a patient, such as the ventilator 30, which may includeany ventilator, such as those available from Nellcor Puritan BennettLLC. The system may also include a monitor 32 that may be configured toimplement embodiments of the present disclosure to determine informationabout blockages in the suction lumen 16 based upon the pressure at thepressure transducer 24 and the pressure transducer 26. It should beunderstood that the monitor 32 may be a stand-alone device or may, inembodiments, be integrated into a single device with, for example, theventilator 30.

The monitor 32 may include processing circuitry, such as amicroprocessor 34 coupled to an internal bus 36 and a display 38. In anembodiment, the monitor 32 may be configured to communicate with thetube, for example via connector 28, to obtain signals from the firsttransducer 24 and the pressure transducer 26. In certain embodiments,the connector 28 may also provide calibration information for the tube12 and/or the pressure transducer 24 and the pressure transducer 26. Theinformation may then be stored in mass storage device 40, such as RAM,PROM, optical storage devices, flash memory devices, hardware storagedevices, magnetic storage devices, or any suitable computer-readablestorage medium. The information may be accessed and operated uponaccording to microprocessor 34 instructions. In certain embodiments,calibration information may be used in calculations for estimating apressure drop between the pressure transducer 24 and the pressuretransducer 26. The monitor 32 may be configured to provide indicationsof blockages in the suction lumen 16, such as an audio, visual or otherindication, or may be configured to communicate the information toanother device, such as the ventilator 22. In addition, themicroprocessor 34 may be programmed with instructions for controllingthe application of the vacuum source 22. For example, a vacuum may beapplied constantly or intermittently.

The pressure transducers 24 and 26 may be any suitable pressure sensorthat may be integrated into the system 10. For example, the pressuretransducers 24 and 26 may be piezoelectric pressure sensors connected toleads be soldered or otherwise coupled to the pressure transducer 24 and26 and may run along the length of suction lumen 16, suction tube 20, orany other tubing or couplers. It should be understood that, while thepressure transducers may be integrated into or onto an exterior wall ofthe lumen 16 or suction tube 20, other contemplated embodiments mayinvolve proximally located pressure transducers 24 and 26 in fluidcommunication, for example through a lumen, with the suction lumen 16 orat various points along the suction pathway.

The connector 28 may be suitably configured to connect to a receivingport on the monitor 32. The connector 28 may contain an informationelement, such as a memory circuit, e.g., an EPROM, EEPROM, codedresistor, or flash memory device for storing calibration information forthe pressure transducers 24 and 26. The connector 28 may also containcertain processing circuitry for at least partially processing signalsfrom pressure transducers 24 and 26 or for interacting with any memorycircuitry provided. When the connector 28 is coupled to the monitor 32,the information element may be accessed to provide calibrationinformation to the monitor 32. In addition, the connector 28 mayfacilitate providing pressure monitoring information to the monitor 32.In certain embodiments, calibration information (e.g., the volume of thepressure transducers 24 and 26, the distance between them) may beprovided in a barcode on the tube or associated packaging that may bescanned by a reader coupled to the monitor 32. The calibrationinformation may also be determined by the monitor 32 as a function ofthe lumen inner diameter and length. Alternatively, the pressuretransducers 24 and 26 may include a passive or active RFID circuit thatmay be read wirelessly to convey pressure monitoring information andcuff calibration information to the monitor 32. In other embodiments therelevant calibration data may be provided in the packaging of the tube12 and may simply be entered manually.

FIGS. 2A-C are exemplary pressure graphs of pressure at PT1 (pressuretransducer 26), pressure at PT2 (pressure transducer 24), and theirdifferential over time as a vacuum suction is applied intermittently.For example, graph 58 in FIG. 2A shows the sensed pressure 59 frompressure transducer 26, graph 65 in FIG. 2B shows the sensed pressure 71from pressure transducer 24, and graph 72 in FIG. 2C shows thedifferential between pressure transducers 24 and 26. During intermittentsuctioning of a clear (i.e., free of blockage) suction lumen 16, thepressure 66 (see FIG. 2B) at pressure transducer 24 is somewhat higherthan the pressure 60 (see FIG. 2A) at the pressure transducer 26. Thisis due to the relative pressure drops of the air flowing through thesuction lumen 16 and the suction tube 20. During intermittent suction,this is seen as a pulse of the characteristic clear pressure 60 atpressure transducer 26 and a pulse of the characteristic clear pressure66 at pressure transducer 24. The difference between the pressure 66 andthe pressure 60 is the characteristic pressure drop 74 (see FIG. 2C)seen with a clear lumen.

When the suction lumen opening 18 becomes covered in secretions so thatthe suction lumen is blocked, the pressure 67 at the second pressuretransducer 24 increases while the pressure 61 at the first pressuretransducer 26 remains constant, which results in substantially nopressure drop between the two transducers 24 and 26. As shown in FIG.2C, equal pressure period 76, showing either no pressure drop or a smallpressure drop where the pressures at pressure transducers 24 and 26 areapproximately equal, may be indicative of a blocked lumen 16. In thedepicted example, the substantially equal pressure period is temporaryas the suction is maintained. The suction, if sufficient to clear theblockage, pulls the secretions through the suction lumen 16 until thesecretions reach the location of the second pressure transducer 26. Atthe point where there is still fluid in the suction line, but the fluidhas passed the pressure transducer 26, the pressure in the pressuretransducer 24 will drop to a pressure 68 that is lower than theunblocked pressure 66. This is because, as opposed to the case of anunblocked tube, the viscous fluid between the two pressure transducers24 and 26 will cause a larger pressure drop 78 relative to the pressuredrop 74 associated with an air-filled tube.

As shown in FIG. 2A, during this period of blockage, the measuredpressure at the pressure transducer 26 remains about the same. That is,the clear pressure 60, the pressure during blockage 61, the pressure 62with fluid between the transducers 24 and 26, and the pressure 63 whenthe fluid has passed transducer 24 and is being evacuated, are generallythe same. These pressures may be compared against a calibration pressure64, which may be obtained by venting the suction tube 20 and measuringthe pressure while the suction tube 20 is empty.

In contrast, as shown in FIG. 2B, the pressure at pressure transducer 24varies throughout the blockage. When the lumen is clear, the pressure 66is lower relative to the pressure 60 at pressure transducer 26. Duringocclusion, the pressure 67 increases and then subsequently decreases topressure 68 and pressure 69 as the fluid is pulled through the lumen andinto the evacuation canister 23. These pressures may be normalized tocalibration case 70.

The variance in pressure at pressure transducer 24 over time because ofblockage in the lumen 16 results in a changing pressure drop, shown inFIG. 2C. In the graph 72, the characteristic pressure drop 74 when thesuction lumen 16 is clear is larger than the lack of pressure drop 76experienced during a period of blockage. When the fluid moves throughthe lumen 16 and into suction tube 20, a larger pressure drop 78 isfollowed by an even larger pressure drop 80 as the fluid is evacuated.These pressure drops may be normalized to the calibration differential82 between the calibration pressures 70 and 64.

The monitor 32 may monitor the pressure and use the resulting pressurepatterns or pressure differentials to determine if the suction lumen 16is blocked. FIG. 3 is an exemplary process flow diagram illustrating amethod for determining lumen blockage based on the pressure at thepressure transducer 24 and the pressure transducer 26. The method isgenerally indicated by reference number 90 and includes various steps oractions represented by blocks. It should be noted that the method 90 maybe performed as an automated or semiautomated procedure by a system,such as system 10. Further, certain steps or portions of the method maybe performed by separate devices. For example, a portion of the method90 may be performed by pressure transducers 24 and 26, while a secondportion of the method 90 may be performed by a monitor 32. Inembodiments, the method 90 may be performed continuously orintermittently for long-term patient monitoring or at any appropriateinterval depending on the particular situation of the intubated patient.

According to a presently contemplated embodiment, the method 60 beginswith a measurement of pressure at a first location at step 92 by thepressure transducer 24 associated with a tracheal tube 12 that has beeninserted into a patient. In addition, at step 94 the pressure transducer26 measures the pressure at a second location. The pressure measurementsmay be communicated to the monitor 32 for further analysis. In addition,the monitor 32 may also receive calibration information from aninformation element or other storage device associated with theconnector 28 that may be used to calculate the pressure. It should benoted that the monitor may, of course, receive data or signals directlyfrom the pressure transducers 24 and 26. At step 98, a pressure drop isdetermined from the pressures measured at steps 92 and 94. Based on thepressure drop from step 98, a monitor 32 may determine whether thesuction lumen 16 is blocked at step 100. For example, if there is acharacteristic pressure drop 74 associated with clear lumen 16, themonitor 32 may determine that the suction lumen 16 is clear. It shouldbe understood that the calculated pressure drop may be within a standarddeviation from the characteristic pressure drop 74. Further, acharacteristic pressure drop 74 may vary from device to device (e.g.,may vary with the size of the tube 12). Accordingly, the particularcharacteristic pressure drop 74 may be calibrated based on empiricalcalibration values that are stored in the connector 28.

If the suction lumen 16 is clear, the method 90 returns to step 92. Inparticular embodiments, prior to the first time that steps 92 and 94 areperformed, the suction line may be vented or occluded so that referenceor calibration baseline pressures (e.g., pressures 64 and 70) at thetransducers 24 and 26 may be collected. The method 90 may be alsoperformed in conjunction with constant or intermittent suctioning. Forexample, in certain embodiments, steps 92 and 94 may be coordinated withthe timing of the application of a vacuum to the suction lumen 16. Insuch embodiments, the measured pressure drop may be determined duringperiods that suction is applied. When the suction lumen 16 is clear, thevacuum may be applied infrequently, such as every ten minutes for aboutfive seconds, unless a blockage is detected.

If, at step 100, the monitor 32 determines that the suction lumen isblocked, for example by detecting an equal pressure period (e.g.,exemplified by a small or substantially no pressure drop as in pressuredifferential 76), the method 90 may apply a vacuum at step 102 so thatthe secretions in the suction lumen 16 can be cleared. The monitor 32may then look for the characteristic pressure drop 74 that indicatesthat the suction is pulling the secretions through the lumen to clearthem at step 104. If the characteristic pressure drop 74 is detected,the monitor may wait until the pressure pattern returns to thecharacteristic pressure drop 74 associated with a clear lumen and thencease applying. In this manner, the vacuum source may be appliedinfrequently and only sustained during periods in which the lumen isblocked. Once the suction lumen 16 is clear, the method 90 returns tostep 92. If, on the other hand, there is no characteristic pressure drop74 and the pressure at the first pressure transducer 26 remainssubstantially the same as the pressure at the second transducer 24, analarm or other indication of blockage may be triggered at step 108 soadditional clearing measures may be taken. In other embodiments, thevacuum force may be increased until the blockage is cleared.

As noted, equal pressure period 76 may predict a blocked lumen 16, whilea pattern of an equal pressure period 76 followed by larger pressuredrops 78 and 80 is characteristic of pressures that occur as the lumen16 is being cleared. Accordingly, equal pressure period 76 may serve asa trigger to continue pressure monitoring to determine if the blockageis being cleared. Further, it should be understood that the monitor 32may determine that a blockage has occurred if any part or combination ofthe a characteristic pressure pattern (e.g., pressure drop 76 followedby characteristic pressures 78 and 80) is detected, including the equalpressure period 76, the pressure drop 78, a larger pressure drop 80, anda return to the normal clear pressure 66 or the normal pressure drop 74.

The monitor 32 may be configured to provide a graphical, visual, oraudio representation of a blockage in the suction lumen 16. For example,a clear lumen 16 may be indicated by a green light indicated on adisplay, while a pressure differential pattern indicating a blockage inthe suction lumen 16 may trigger an alarm, which may include one or moreof an audio or visual alarm indication. In one embodiment, the alarm maybe triggered if a change from the characteristic pressure drop 74 issubstantially greater than a predetermined value, substantially lessthan a predetermined value, or outside of a predetermined range.

While a blockage in the suction lumen 16 may be detected by indirectmeasurements of the pressure differential at proximal locations alongthe suction path, the buildup of secretions around the lumen opening 18may be directly measured by appropriately placed sensors. FIG. 4 is aperspective view of an exemplary tracheal tube 12 according to certainpresently contemplated embodiments. The tube 12 includes a cuff 14 thatmay be inflated via inflation lumen 42. The cuff 14 may be connected tothe tube 12 via a proximal shoulder 114 and a distal shoulder 116. Asuction lumen 16 may be formed in the tube walls running parallel to theairflow path of the interior airflow lumen 118. The suction lumen 16terminates in opening 18, located above the proximal shoulder 114. Thetube 12 forms a slight curve along its length for ease of insertion intothe patient. The curve defines an inside face 120 of the tube that, wheninserted into the patient, faces dorsally. The opening 18 may be locatedon the inside face 120. A secretion sensor 122 is located on the tube 12between the opening 18 and the proximal shoulder 114. When the tube 12is inserted into a patient, secretions may build up on the cuff 14.These secretions first encounter the secretions sensor 112 beforereaching the level of the cuff. The secretion sensor 122 is configuredto communicate with a monitor 32 to provide an indication of secretionsbuildup. As shown, an imaginary axis 124 drawn through the secretionsensor 122 and the opening 18 may be approximately parallel to theairflow path. In other embodiments, the secretion sensor 122 may beplaced at other circumferential locations on the tube 12 between theopening 18 and the proximal shoulder 114.

The secretion sensor 122 may be a pressure sensor, a capacitive sensor,a gas sensor, a thermal sensor, or a conductive sensor. For example, athermal sensor may experience an increase in temperature as secretionssurround it. A gas sensor may experience a decrease in detected gas inthe ambient air as the secretions block the gas from encountering thesensor 122. The information provided by the secretion sensor 122 may beused to control the application of a vacuum to the suction lumen 16. Incertain embodiments, a vacuum may only be applied when secretions aredetected. The tube 12 may include a connector 28 that facilitatescoupling of the sensor 122 to a patient monitor, e.g., monitor 32. Inaddition, the tube 12 may include an addition lumen (not shown) foradding saline or another fluid to the secretions to decrease theirviscosity and aid suctioning. Alternatively, the lumen 16 may be used todeliver saline.

When a tracheal tube 12 is inserted into a patient, the patient isgenerally in an inclined position. Shown in FIG. 5 is a side view of atracheal tube 12 inserted into a patient airway. As secretions 128 flowdown from the mouth, they begin to build up above the cuff 14. However,because the tracheal tube 12 is at an incline, the secretions may spreadaround the area above cuff 14, leaking from the dorsal side 130 to theventral side 132 (shown by arrows 134). In addition, the secretions mayspread in a proximal direction, forming a pool around the opening 18. Inone embodiment, a tracheal tube may include any number of additionsecretion sensors, e.g., secretion sensors 122 a, 122 b, 122 c, and 122d, placed at appropriate locations around the tube 12 to provideinformation about the extent of the secretion buildup. For example, thesecretion sensor 122 a is between the opening 18 and the proximal cuffshoulder 114, and the secretions sensor 122 b is above the opening 18.The secretion sensor 122 b may provide information about the extent ofpooling around the opening 18. Pooling may be more extensive if bothsensors 122 a and 122 b are covered. Additionally, secretion sensors 122c and 122 d may be located towards the ventral side 132 to detectleaking of secretions around the cuff 14. Similarly, FIG. 6 illustratesa side view of a region of the tube 12 surrounding an opening 18. Inthis alternative embodiment, the secretion sensor 122 may be annular orsemi-annular so that the secretion sensor 122 at least partiallysurrounds the opening 18. The secretion sensor 122 may be configured sothat an indication of secretion buildup may include information aboutthe percentage of the annular opening 18 that is covered. In anotherembodiment, rather than a single annular secretion sensor 122surrounding the opening 18, a tube 12 may include a plurality ofindividual secretion sensors 122 that surround the opening 18.

Secretion sensors 122 may also be associated with multiple suctionlumens 16 to that may provide redundant suctioning functionality. Asshown in FIG. 7, a side view of a region of a tube 12 above the cuff 14,the tube 12 may have multiple suction lumens 16 (shown as 16 a and 16b), each terminating in respective openings 18 a and 18 b. Secretionsensors 122 a and 122 b may be associated with each opening 18. If, forexample, suction lumen 16 a is blocked, as indicated by secretion sensor122 a, suction may be redirected to suction lumen 16 b until suctionlumen 16 a is cleared.

As provided herein, a tube 12 may be associated with a suction systemthat includes connectors configured to couple the lumen 16 to a vacuumsource 22 and a fluid collection canister 23. The vacuum source 22 maybe provided as a standard vacuum pumping system and may include anysuitable regulator to control the flow of the negative pressure. Forexample, a vacuum pump set to −100 mm Hg may be reduced to −20 mm Hgsuctioning pressure via a valve. In addition to a vacuum source, asystem 10 may also include a source of positive pressure air. In certainembodiments, when a suction lumen 16 is blocked, a combination ofnegative pressure air and positive pressure air may be used to clear theblockage.

FIG. 8 is an exemplary suctioning system 150 that includes a vacuumsource 22 coupled to a positive pressure unit 152 via suction line 154,which is coupled via any appropriate combination of tubing andconnectors to suction tube 20 and suction lumen 16. The positivepressure unit includes a pressurized air source 155 that may be coupledto the suction line 154 via a one-way valve. The vacuum source 22 isregulated by valve control 156. When a downstream blockage in thesuction lumen 16 is detected, for example via a change of pressuredetected at one or more pressure transducers 157 associated with suctionline 154, suction tube 20, or suction lumen 16, the valve control 156may increase the vacuum pressure applied to line 154 (e.g., from −20 mmhg to −50 mm Hg) in an attempt to clear the blockage. If, after a periodof time, the pressure does not drop, indicating that the lumen is notclear, the positive pressure from the positive pressure unit 152 may beblown air down the suction line 154 to clear the blockage. Thepressurized air is then used to eject the mucus plug from the lumen backinto the trachea.

The valve control 156 may increase the vacuum pressure and duration ofits application through additional cycles. For example, duringadditional cycles, vacuum pressures of −70 mm Hg and −90 mm Hg may beused. After each vacuum pressure cycles, positive pressure may beapplied, even if the lumen is not yet clear. The cycle of alternatingnegative and positive pressure may break up the secretions, allowingthem to be more easily cleared through the lumen 16. That is, thesecretions may be broken into smaller pieces or may be in more liquidform that is less likely to block the lumen 16.

Positive pressure unit 152 is coupled to the suction line 154 so that asource of pressurized air 156 is able to provide positive pressure airinto the suction line 154. In one embodiment, the positive pressure unitmay be a unitary device that has an upstream connector 158 and adownstream connector 160 so that the positive pressure unit 152 may beconnected in-line with the suction line 154. As such, the positivepressure unit 152 may be provided as an upgrade to an existingsuctioning system. The positive pressure unit 152 may include processingcircuitry, such as a microprocessor 162 and a display 164 that mayprovide indications or alarms related to detected blockages. Thepositive pressure unit 152 may also include a control input 166, such asa keyboard or touch screen, that allows an operator to change settings,such as settings related to the pressure of the air blown into thesuction line 154. The positive pressure unit 152 may also communicatewith one or more pressure transducers 157. Further, the positivepressure unit may communicate with the valve control 156 so that thevacuum pressure and the positive pressure may be appropriatelyalternated to facilitate clearing any blockages.

FIG. 9A is an cross-sectional view of a positive pressure system 170that provides positive pressure air into the suction line 154 withoutusing a pressurized air canister. When the lumen 16 becomes blocked, thepressure of the air in the suction line 154 increases. The positivepressure system 170 uses the increase in energy to pressurize ambientair. When the suction line 154 experiences increased negative pressure,the pressure increase pulls a flap 172 and a moveable member, shown asdeformable membrane 174, towards the suction line 154. This movement inturn creates a vacuum that draws air, shown by arrow 176, into chamber178 through one-way valve 180. In other embodiments, the moveablemembrane may be a piston or a spring-loaded cylinder.

When the vacuum pressure in the suction line 154 passes a thresholdwhere the spring force or the deforming force of the moveable member ishigher than that of the suction line 154, the moveable member will bereleased and will drive the air out of the change through flap valve184. As shown in FIG. 9B, the air, represented by arrow 186, then entersthe suction line 154. It should be understood that the size of thechamber 178 and the deforming or spring-force characteristics of themoveable member may be selected to facilitate injection of air into thesuction line 154 at particular pressure points in the suction line 154.

While the disclosure may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the embodiments provided hereinare not intended to be limited to the particular forms disclosed.Rather, the various embodiments may cover all modifications,equivalents, and alternatives falling within the spirit and scope of thedisclosure as defined by the following appended claims.

What is claimed is:
 1. A system, comprising: a tracheal tube configuredto be inserted into a patient's airway, wherein the tracheal tubecomprises: a conduit having a proximal end and a distal end; aninflatable cuff surrounding the conduit, wherein the inflatable cuff isconfigured to seal the airway; a first suction lumen formed in a wall ofthe conduit and terminating in a first opening proximal to theinflatable cuff; a first sensor disposed on the wall of the conduitbetween the inflatable cuff and the opening, wherein the first sensor isadjacent to the opening and configured to detect secretion build-upabove the inflatable cuff; a second sensor disposed on the wall of theconduit adjacent to the inflatable cuff and opposite the first sensorand the opening; and a monitor communicatively coupled to the trachealtube and comprising a processor configured to receive information fromthe first sensor and the second sensor, wherein the processor controls avacuum system configured to suction the secretions based on theinformation.
 2. The system of claim 1, wherein the first sensor at leastpartially surrounds the opening.
 3. The system of claim 1, wherein thefirst sensor is configured to detect a percentage of the first openingcovered by the secretion build-up.
 4. The system of claim 1, wherein thesecond sensor is configured to detect secretion leakage around theinflatable cuff.
 5. The system of claim 1, comprising a second suctionlumen formed in the wall of the conduit and terminating in a secondopening proximal to the inflatable cuff.
 6. The system of claim 5,wherein the second opening is co-axially aligned with the first opening.7. The system of claim 5, wherein the second opening is associated withthe second sensor.
 8. The system of claim 5, wherein the second suctionlumen removes the secretions when the first suction lumen is blockedwith the secretion build-up.
 9. The system of claim 1, wherein thesecond sensor is positioned on a ventral side when the tracheal tube isinserted into the patient's airway.
 10. The system of claim 1, whereinthe first sensor is positioned on a dorsal side when the tracheal tubeis inserted into the patient's airway.
 11. A method, comprising:determining a first pressure associated with a suction lumen formed in awall of a tracheal tube configured to be inserted into a patient'sairway, wherein the suction lumen is in fluid communication with a firstpressure sensor configured to measure the first pressure; measuring asecond pressure associated with the suction lumen with a second pressuresensor spaced apart from the first sensor; determining a pressuredifferential between the first pressure and the second pressure, whereinthe pressure differential is indicative of secretion blockage in thesuction lumen; detecting a characteristic pressure drop between thefirst and second pressure sensors; and applying a vacuum to the suctionlumen based on the pressure differential and the characteristic pressuredrop.
 12. The method of claim 11, comprising removing the vacuum fromthe suction lumen when the characteristic pressure drop is detected. 13.The method of claim 12, wherein the suction lumen is blocked when thefirst pressure and the second pressure are the same.
 14. The method ofclaim 11, wherein the suction lumen is clear when the pressuredifferential is equal to the characteristic pressure drop.
 15. Themethod of claim 11, comprising positioning the first pressure sensor andthe second pressure sensor on a suction tube fluidly coupled to thesuction lumen, wherein the suction tube is exterior to the patient whenthe tracheal tube is inserted.
 16. The method of claim 11, displayinginformation associated with secretion blockage in the suction lumen on amonitor communicatively coupled to the tracheal tube.
 17. A system,comprising: A monitor coupled to a tracheal tube inserted in a patient'sairway and comprising: a processor configured to receive a first signalfrom a first pressure sensor and a second signal from a second pressuresensor fluidly coupled to a suction lumen formed in a wall of thetracheal tube, wherein the first and second signals are indicative of apressure within the suction lumen, and wherein the processor comprisesinstructions configured to: determine a pressure differential betweenthe first and second signals, wherein the pressure differential isindicative of secretion blockage in the suction lumen; compare thepressure differential with a characteristic pressure drop associatedwith an unblocked suction lumen; control a vacuum source configured toremove the secretions through the suction lumen based on the pressuredifferential and the characteristic pressure drop.
 18. The system ofclaim 1, wherein the suction lumen is clear when the pressuredifferential is equal to the characteristic pressure drop.
 19. Thesystem of claim 1, wherein the first pressure sensor and the secondpressure sensor are external to the patient with the tracheal isinserted.
 20. The system of claim 1, wherein the monitor provides agraphical, visual, or audio representation of the secretion blockage inthe suction lumen.